Re: ADA mp1 help needed

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Author: Kaz Kylheku
To: anthony.i.lee
CC: ADA MP-1 List
Subject: Re: ADA mp1 help needed

Also, take a look at this Switchcraft catalog:

Specifically, starting on P. 79 they have their well-known "zoo" of switch configurations, numbered with roman numerals.

Look at XV.  That looks awfully like the ADA MP-1 effect return jack.

Also look at XIX. That configuration would work also.

These roman numeral designations are used elsewhere in the document to identify jack types (not only 1/4" jacks, mind you).

On 14.01.2014 16:07, Kaz Kylheku wrote:

Hi Anthony,

Firstly, what is wrong with the jack? Maybe it doesn't need replacing.

I don't have experience replacing that particular jack, but here is some general advice:

  • Don't try to look for a PCB-mounted part which matches the footprint. Just forget it! Put in a panel-mounted jack and use hookup wires between that and the PCB.
  • Check this schematic: As you can see, this is is a stereo jack with 6 terminals: three for the jack itself, and three for a SPDT switch which is in one position when nothing is plugged in and the other position when there is a plug.
  • Although it's a stereo jack, note that the ring connection is not used; the diagram just shows the ring connection as being connected to the switching assembly mechanically, but it has no electronic connection. Therefore, a mono jack (tip-sleeve) with a SPDT switch (5 terminals in total) would work in this application. The SPDT switch controls which source feeds the return. When nothing is plugged in, the switch connects the return circuit directly to the send circuit (bypassing the loop's send and return buffering and level control op-amps). When the plug is inserted, the switch connects the return to the output of the return op-amp.

Check out this puppy: stereo jack, with two SPDT switches: 9 pins!  You'd just use five of these connections. Can't vouch for its audio quality though. Both switches could be wired in parallel to provide redundancy, I suppose.

On 11.01.2014 08:22, anthony.i.lee wrote:

Do you know what effects return jack for the ADA MP1
what is it & where can I get one

Anthony Lee